The Sekor A
200
mm
f/2.8
APO (apochromatic) is part of the final generation of Mamiya manual
focus lenses, and was not replaced in the subsequent AF series of
lenses for the 645AFD. This lens is considered by many photographers,
including this author, to be one of the outstanding optical
designs produced by Mamiya. The example I acquired used, in the United
States some years ago, was later readjusted by Mamiya in Japan, and
delivers centre sharpness of 120 lp/mm which is exceptional by any
measure.
For comparison, the centre sharpness of this apochromat is essentially
more than 50% greater than the sharpness of typical and very good Sekor
C series primes, while the lens also delivers exceptionally high
contrast. Peak sharpness on this example is observed at f/5.6 and f/8.0.
The Sekor A
200
mm
f/2.8
APO performs equally well on the 645AFD, as it does on Nikon DSLRs.
Sekor A 200 mm f/2.8 APO Lens
mounted on a Nikon D90 with a Fotodiox Pro adaptor, April, 2011 (HS10
10 MP).
Sekor A 200 mm f/2.8 APO Lens
mounted on a Mamiya 645AFD, October, 2010 (HS10 10 MP).
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A 2011 acquisition was a Fotodiox
Mamiya/Nikon adaptor modified by Legacy2Digital in the US with a
digital emulator chip, which presents the lens to the camera body as a
Nikon device. It is preprogrammed to represent the 200 mm f/2.8 APO
with the proper focal length and maximum aperture. This enables the
full range of automated features in a Nikon body, in this instance a
D90.
Sekor A 200 mm f/2.8
APO Lens Test Targets (D90 DX/APS-C)
Test
target
using
the
same
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D90
at 220
ISO
and
1/4000. Uncorrected 12.3 Megapixel original - the DX
sensor crop factor produces similar effect to
a single 2XN teleconverter
[Click image to view full size].
Test
target
(above, below) using
the
same
200
mm
f/2.8
APO
manual
focus
lens
with
single
Kenko M45 2XN
teleconverter
at
f/4.0
mounted
on a
Nikon D90 at 800
ISO and 1/2000. Uncorrected 12.3 Megapixel
originals. This configuration produces the same angular coverage as the
lens with two stacked 2XN teleconverters. Handheld shot as the moment
produced by the lens and teleconverter was judged to be great enough to
damage the tripod clamp [Click image to view full size].
Test
target
using
the
same
200
mm
f/2.8
APO
manual
focus
lens
with
two
stacked
2XN
teleconverters
at
f/4.0
mounted
on a Nikon D90 at 800
ISO
and
1/1600.
Uncorrected 12.3 Megapixel original. This configuration produces
the
same angular coverage as the lens with three stacked 2XN teleconverters.
Handheld shot as the moment produced by the lens and pair of
teleconverters was judged to be great enough to damage the tripod clamp
[Click image to view full size].
Sekor A 200 mm f/2.8
APO Lens Test Shots (D800 FX/FF)
Palm tree
test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 2000
ISO
and
1/5000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Lemon tree
test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 2000
ISO
and
1/5000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Ceramic pig
test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 560
ISO
and
1/8000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Sage
blossom test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 1250
ISO
and
1/5000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Garden weed
test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 1250
ISO
and
1/2000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Domestic
cat test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D800
at 1250
ISO
and
1/8000, using the Legacy2Digital modified
adaptor. 36
Megapixel
original cropped and adjusted for exposure using Aperture 3, reduced to
1024 pixels width, and below, 1:1 1024^2 pixel crop
[Click image to view 1:1 resolution].
Sekor A 200 mm f/2.8
APO Lens Test Shots (D90 DX/APS-C)
Feline
test
target
using
the
same
200
mm
f/2.8
APO
manual
focus
lens
at
f/5.6
mounted
on
a
Nikon
D90
at 1100
ISO
and
1/1600, using the Legacy2Digital modified
adaptor. 12.3
Megapixel
original cropped and adjusted for exposure using Aperture 3. Note the
reflection in the left eye at 1:1
[Click image to view 1:1 resolution].
Test
target
(Grevillia Banksii) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 640
ISO and 1/1600, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Lemon blossom) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 1600
ISO and 1/1000, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Plum blossom) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 400
ISO and 1/3200, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Buttercup oxalis blossom) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 1100
ISO and 1/1600, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Sage blossom) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 1600
ISO and 1/1600, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Australian Magpie) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 900
ISO and 1/1600, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
(Spotted Turtle Dove) using the
200 mm f/2.8 APO
manual focus lens mounted on a
Nikon D90 at 800
ISO and 1/800, using the Legacy2Digital modified adaptor. 12.3
Megapixel
original cropped and adjusted using Aperture 3
[Click image to view 1:1 resolution].
Test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/8.0
mounted
on
a
Nikon
D90 at 200
ISO and 1/1600. Uncorrected 12.3 Megapixel
original. This configuration produces the same angular coverage as the
lens with one 2XN teleconverter. Handheld shot from ~2.5 metres [Click
image to view
full size].
Test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/4.0
mounted
on
a
Nikon
D90 at 250
ISO and 1/1000. Uncorrected 12.3 Megapixel
original. This configuration produces the same angular coverage as the
lens with one 2XN teleconverter. Handheld shot from ~2.5 metres [Click
image to view
full size].
Test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/4.0
mounted
on
a
Nikon
D90
at 800
ISO
and
1/400. Above, uncorrected 12.3 Megapixel
original, below enhanced using Aperture 3. This configuration
produces the same angular coverage as the lens with a 2XN
teleconverter. Handheld shot as the moment produced by the lens was
judged to be great enough to damage the tripod clamp
[Click image to view full size].
Above:
Test
target
using
the
200
mm
f/2.8
APO
manual
focus
lens
at
f/8.0
mounted
on
a
Nikon
D90 at 320
ISO and 1/500. Uncorrected 12.3 Megapixel
original. This configuration produces the same angular coverage as the
lens with one 2XN teleconverter. Handheld shot from ~2.5 metres [Click
image to view
full size]; below: 1:1 crop of same, note the
ant at full
size to the upper left of the lime fruit - the left antenna is
distinguishable, but the eyes are not. Third image is
enhanced using Aperture 3.
|
Sekor A 200 mm f/2.8
APO Lens Test Targets (645AFD Film)
Test
target
using
a
200
mm
f/2.8
APO
manual
focus
lens
at
f/2.8
in
an
800
mm
arrangement
with two stacked 2xN
teleconverters, with Fuji Pro 160C. Above is uncorrected original
reduced from 1300 PPI scan, below same after correction for chromatic
aberration using Photoshop.
1:1
crops
of
test
target
using
a
200
mm
f/2.8
APO
manual
focus
lens
at
f/2.8
in
an
800
mm
arrangement with two stacked 2xN
teleconverters, with Fuji Pro 160C. Above is uncorrected original at
1300 PPI scan resolution, below same after correction for chromatic
aberration using Photoshop.
|